*{
    padding: 0;
    margin: 0;
    list-style: none;
}
.box{
    width: 721px;
    height: 454px;
    border: 1px solid black;
    overflow: hidden;
    position: relative;
}
ul{
    display: flex;
    position: absolute;
    top: 0;
    left: 0;
}
.box span{
     display: block;
     width: 30px;
     height: 40px;
     font-size: 30px;
     font-weight: bold;
     color: white;
     background-color: lightslategray;
}
.box .left1{
    position: absolute;
    top: 40%;
    left: 0;
    display: none;
}
.box .right1{
    position: absolute;
    top: 40%;
    right: 0;
    display: none;
}
.dot{
    position: absolute;
    bottom: 20px;
    left: 40%;
}
.dot a{
    display: inline-block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background-color: burlywood;
    margin-right: 10px;
}
.dot .info{
    background-color: crimson;
}